Janet Yellen will make history as the first woman to lead the Federal Reserve, becoming its chairwoman at a key moment for the central bank as it attempts to unwind its unprecedented efforts to boost the economy in the aftermath of the financial crisis.

The Senate voted 56-26 on Monday to confirm Yellen to replace Chairman Ben Bernanke, whose term expires Jan. 31. Yellen, who has been vice chairwoman of the Fed since October 2010, is expected to begin her new post Feb. 1.

While Bernanke navigated the Fed through the 2008 financial crisis and the ensuing recession during his eight year tenure, it will be Yellen’s job to manage the retreat from these policies as the economy gains strength and is better able to stand on its own.

The Fed has spent recent years buying massive piles of Treasury and mortgage bonds through so-called quantitative easing — its balance sheet is now more than $4 trillion — in an effort to keep long-term interest rates low and spur on the economy. How to exit this program and then shrink the balance sheet without rattling financial markets and hurting the economy will be job number one for Yellen.

“Her biggest potential challenge is not the end of quantitative easing, but rather, the eventual unwinding of the massive Fed asset positions and rolling back of the Mount Everest of reserves the Fed has created,” said Kevin Hassett, a senior fellow at the conservative American Enterprise Institute and a former economist at the Federal Reserve. “If the economy picks up a bit from here, that challenge will be a difficult one, as inflationary pressures will begin to ramp up.”

The Fed has already begun slowing its asset purchases citing the improving economy — this month it reduced its monthly bond buys by $10 billion to $75 billion — easing the transition somewhat for a Yellen-led Fed.

Yellen, 67, is also poised to take over the central bank at a time when it faces greater congressional scrutiny from conservatives and liberals alike, both for its massive efforts to jump start the economy and because of the increased responsibility the Fed has assumed for regulating Wall Street under the 2010 Dodd-Frank law.

Republicans have used Yellen’s nomination to bash the Fed’s easy-money policies warning they are fueling stock market “sugar highs” and possible asset bubbles while serving as a prelude to an inflation spike. The evidence, so far, does not support worries over inflation, deflation has been more of a concern, but Republicans have kept sounding the alarm.

“While the stock market has become addicted to easy money, the benefit to Main Street has been questionable at best,” Sen. Charles Grassley (R-Iowa) said on the floor Monday. “Unemployment remains high. Bank lending remains tight. And savers are discouraged.”

Democrats praised Yellen as being the right person to lead the Fed at this moment.

“The American people will have a fierce champion who understands that the ultimate goal of economic and financial policymaking is to improve the lives, jobs and standard of living of American workers and their families,” President Barack Obama said of Yellen in a statement following the vote.

In a sign of the increasing partisanship over the central bank, Yellen received the fewest votes of any Fed chair. Bernanke held the previous low when he was confirmed to a second four-year term in 2010 on a 70 to 30 vote. Not all senators voted on Monday, however, in part due to bad weather in sections of the country.

Senate Democrats pushed for a vote on Yellen’s nomination last month, but Republicans refused unless a vote was also held on an “Audit the Fed” bill, which would put the central bank’s monetary policy making under greater congressional scrutiny.

The intense congressional interest in the Fed is not going away now that Yellen has been confirmed.

House Republicans plan a year long-effort to put the Fed under the microscope.

The House Financial Services Committee is celebrating the Fed’s centennial by launching an “oversight project” that will examine the Fed’s role in financial markets and the economy, with a bill making changes to how the central bank operates expected late this year.

“It will be the most rigorous examination and oversight of the Federal Reserve in its history,” committee Chairman Jeb Hensarling (R-Texas) said last month when announcing the initiative.

This “oversight project” is emblematic of conservatives’ unease with the Fed and Republican criticism that it has gone too far in recent years in trying to boost the economy, pointing to these efforts as another example of government overreach.

Dealing with congressional attention is now a bigger part of the Fed chair’s job than when Bernanke first filled the seat in 2006 — following years of lawmakers taking a more hands off approach during the long tenure of Chairman Alan Greenspan.

In recent weeks, Bernanke has acknowledged the increased role Congress plays in the life of a Fed chairman, pushing back against critics — in his polite professorial tone — while being careful to say the Fed should welcome oversight from elected officials.

Asked what advice he would offer Yellen for dealing with lawmakers, Bernanke said in a December press conference: “Congress is our boss.”

“They represent the public, and they certainly have every right to set the terms on which the Federal Reserve operates and so on,” he said.

But he’s also dismissed arguments by the central bank’s most ardent congressional critics that its monetary policy making should be made more transparent — warning that the “Audit the Fed” movement would lead to too much political pressure from Congress on an independent agency and that its critics ignore how much more transparent the Fed has become on his watch.

“The Federal Reserve routinely makes public extensive information on all aspects of its activities, and since the crisis it has greatly increased the quantity and detail of its regular reports to the Congress and the public,” Bernanke said in a Jan. 3 speech at the annual meeting of the American Economic Association.

Yellen will not only have to be mindful of scrutiny from the right — liberal lawmakers are also watching the Fed carefully.

Under Dodd-Frank, the Fed was given more authority to oversee the country’s largest financial institutions and liberal lawmakers want it to take an aggressive stance toward Wall Street and write tough rules for big banks.

This tension was evident last year when liberal members of the Senate Banking Commitee — Brown, Jeff Merkley (D-Ore.) and Elizabeth Warren (D-Mass.) — signaled to the White House they were against nominating Larry Summers as Bernanke’s replacement.

Summers’ role in deregulating financial markets as part of the Clinton administration as well as the perception that he was against some of the tougher policies toward banks pitched by Brown and Merkley during the writing of Dodd-Frank, rankled liberals.

Summers withdrew his name from contention in September in the face of this opposition, clearing the way for Yellen to be nominated.

Yellen has supported some of the Fed’s most aggressive efforts to crackdown on big banks, such as new capital rules, but she also has not given any indication that she plans to go beyond what the Fed has already done or discussed. While liberals have cheered her nomination, Yellen may disappoint Wall Street critics if the “too big to fail” debate continues and she maintains the status quo approach.

On monetary policy, Yellen and Bernanke have been allies and financial markets don’t expect a change once she becomes chairwoman.

Yellen has been an advocate of the Fed more clearly communicating its monetary policy approach and what factors will contribute to future decisions.

The success of this strategy has been mixed. Financial markets got spooked in June following a Bernanke news conference where his remarks were interpreted as indicating the Fed would back off its overall stimulus efforts in late 2013 or early 2014.

The announcement last month that the Fed would begin scaling back its monthly bond buys went more smoothly as the Fed made clear that even as it “tapers” these asset purchases it will keep short-term interest rates low for the forseeable future.

Effective communication will be one of Yellen’s biggest challenges as market watchers navigate the wind down of quantitative easing.

“The market and the Fed do not have a relationship built on effective communication and that must improve in 2014 for Janet Yellen to be successful as she steers the Fed into taking a less direct role in influencing the market,” said Jeff Kleintop, chief market strategist at LPL Financial. “When it comes to relationships and communicating, if men are from Mars and women are from Venus, the Fed is from Neptune.”